1. Field of the Invention
The present invention relates to processes of hydrometallurgical treatment for eliminating metal impurities from a solution containing dissolved metals to be extracted and, more particularly, to such processes for eliminating iron impurities from a zinc sulfate solution.
2. Description of the Prior Art
In hydrometallurgy as currently practiced, there are in general three principal industrial processes for selectivity eliminating iron as a decantable and filterable residue from zinc sulfate solutions resulting from the chemical attack of oxidized zinc ores, more particularly roasted zinc ores. The iron residue is largely made of jarosite, geothite or hematite depending upon the particular process involved. The known processes are, however, subject to the drawback that the iron residues resulting therefrom are generally without any significant commercial or industrial value and the proper disposal of the residues poses serious practical and environmental difficulties. Furthermore, the known processes involve expensive and complex facilities for their realization, when making allowances for the flow rates and retention times involved.